Cetral nervous system - seizures Flashcards
What are the different types of seizure
Two main types
1) Partial seizures - further subdivide in to 3 subtype
a) Simple partial seizure ( no LOC)
b) Complex partial seizure ( impairement of consciousness)
c) Secondary generalised seizure ( LOC)
2) Generalised seizure - further subdivide into subtypes
a) Non convulsive ( abscence or Petite Mal seizure)
b) Tonic - convulsive ( Grand Mal seizure)
c) Todds paralysis
d) Tonic or clonic or atonic
e) Myoclonic jerks
What are the causes of seizures
1) Idiopathic - 5 to 20yrs old , epilepsy if recurrent
2) Congenital - prenatal injuries
3) Metabolic - hypoglycemia, hyponatremia, hypocalcemia, phenylketonuria
4) Traumatic - occurs within 2 years, esp pierce dura
5) Space occupying lesion - middle to later in life, 13% new seizures in 35 to 64 yrs old - Neurocysticercosis
6) Vascular - AVM, SAH, CVA
7) Degenerative - Alzheimers
8) Infection - Meningitis, encephalitis, ( most common in 5 - 15yrs old)
9) Drugs - stimulants, theophyline, TCA, Alcohol withdrawal, Isoniazid
10) Eclampsia
What are the differential diagnosis of Seizures
1) All the causes of syncope
2) TIA
3) Migraine
4) Movement disorder
5) Sleep disorder
6) Psychogenic
7) Eclampsia
Diagnosis of seizures
1st Seizure
- low HCO3, low PO2, high lactate, Raise WBC
- Check electrolytes - sodium, glucose, calcium and magnesium
- urine - pregnancy , toxicology
- CT head if suspect structural lesion
- LP if suspect meningitis or SAH
- If HIV - CT + contrast or MRI if no explanation
Recurrent Seizure
- Check glucose and anticonvulsant levels ( if available)
- same nature of seizure - DC
- Change in seizure pattern, fever, Status Epilepticus
Indications for immediate CT
- Structural lesion suspected
- new focal neurological deficit
- Persistently altered mental status
- fever
- recent trauma
- history of cancer
- anticoagulation
- Suspicion of HIV
- Different seizure pattern
- age > 40
- Partial onset seizure
What is the role of EEG in the management of seizure
- Most useful in diagnose if perform within 48hrs after seizure . Positive in 70%
- Can detect abnormal brain waves and event localize the area - use for prognostication / likelihood of recurrence
- 50% positive if only on EEG done - need to repeat if story is good and the first EEg normal
What are the predictors of recurrence in Adults
- age < 50
- Family history of epilepsy
- second seizure within 1 week
- Cerebral tumour as cause
- Prior neurologic injury or insult
Predictors of recurrence in children
- abnormal EEG
- Seizure onset during sleep
- History of febrile seizure
- Todds paresis
( Abscess of above - 20% recurrence rate)
Most recurrence occur < 2 yrs
What is Status epilepticus
- 2 or more seizures without full recovery between sizure
- 5 minute of continuous convulsive seizures
- Seizure on arrival in ED > 20min
Causes of Status epilepticus
- anticonvulsant withdrawal
- other drug witdrawal - alcohol, benzo, baclofen
- Cerebral event
- Metabolic - hypoglycemia, hyponatremia, hypocalcemia
- Trauma
- Drug toxicity - TCA, clozapine, Theophyline
- CNS infection- encephalitis
- tumour
Complications of Status epliepticus
a) Resp
- hypoxia, hypercarbia ( resp failure or aspiration)
b) CVS
- hypotension, cardiac failure, arrhythmia
c) Metabolic
- Hypoglycemia, electrolyte disorders, hyperthermia, rhabdomyolysis, DIC
d) Trauma from seizure
- head injury, Tongue larceration, Dental injury, fracture of upper lumbar vertebra, posterior shoulder dislocation
e) Circumstances of seizure
- drowning, electrical injury, thermal or blunt trauma
What are the 2 phases of physilogical changes during status epilepticus
Phase I - fight and flight state
- hypertension, tachycardia, hyperglycemia, hyperreflexia
- increase CBF and metabolism
- Hyperpyrexia, sweating salivation, lactic acidosis
- Raise WBC
Phase II - transition to phase 2 mark the onset of irreversible cerebral damage after 30 min
- fail of compensatory mechanism
- hypotension, hypoglycemia hypoxia , reduce CBF
- Arrhythmia, cardiac failure, renal, hepatic and coagulation failure
What are the cause of hypoxia in status epilepticus
- CNS failure
- increase demand
- impaired ventilation due to pulmonary oedema and aspiration
What investigation would you carry out during status epilepticus
a ) bed side
- bedside glucose, Urine toxicology + pregnancy
- ECG , ABG
b )Laboratory
- FBC, Electrolyte, Glucose, Anticonvulsant levels
- Total CK
c ) Imaging once seizure is control or intubated and paralysed
- CXR, CT head +- neck if siugnificant trauma, MRI
EEG useful to monitor paralysed patient
Describe your management of this patient
Supportive
Drug therapy
